Pulverizing or grinding machine.



E. J. $TEGKLE.

PULVERIZING 0R GRINDING MACHINE. APPLICATION FILED JULYZG, 1913.

Patented Apr. '7, 19M

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Specification 6r Letters Irate'nt.

Patented Apr. 2, 191d.

Application filed July 26, 1913. Serial No. ?81,4i23.

To all whom it may concern:

Be it known that I, EDWARD J. STECKLE, a citizen of the United States, residing at El Paso, in the county of El Paso and State of Texas, have invented a new and useful Pulverizing or Grinding Machine, of which the following is a specification.

This invention has reference to improvements in pulverizing or grinding machines, and its object is to provide means whereby the output of the pulverizing mill may be largely increased.

In accordance with the present invent-ion air is exhausted from the pulverizer or grind ing mill, carrying with it an amount of pulverized material, and this air stream, caused by a suitable fan, is directed into a separator, which may be of the cyclone type, and the air freed from the pulverizedmaterial is returned to the pulverizing or grinding zone of the mill, and in-this return pipe there is provided a valve vent acting as a relief for surplus air. In order -to establish an induced draft through the mill the outlet pipe or duct therefrom leading to the usual conveyor for the pulverized material has connected thereto an auxiliary pipe which may be of less diameter than either the outgoing or inflow pipe for air, and this auxiliary pipe is connected to the suction duct or pipe close to the fan. Moreover, the collecting member of the cyclone separator is arranged for discharge into the conveyer receiving pulverized material from the mill.

The present invention has been found in practice to be especially useful in connection with pulverizing limestone and cement clinker, and practice has demonstrated that it increases the output of the mill nearly or quite one hundred per cent, and, furthermore, gives a finer productthan heretofore, such fine product being very desirable in the manufacture of Portland cement and other materials that require fine grindin The invention has to do particu arly with pulverizingmachines' using screens for separation, and as nearly every such mill requires fineness of ninety per cent, passing a two hundred mesh screen, it has been found impossible to get more than about one-half of the grinding capacity of the mill through the screens, articularly if the material be slightly amp. The present invention relieves the mill of all dampness and takes care of the surplus material, while the returned air causes a constant agitation in the grind- IIIgZOIlB of the mill, and this increased agie tation gives larger output.

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompany'ing drawings forming part of this specification, with the further understanding that while the drawings show a practical form of the invention, the latter is not confined to any strict conformity with the showing of the drawings, but may be changed and modified so long as such changes and modifications mark no material departure from the salient features of the invention.

In the drawings there'is shown partly in elevation and partly in section an arrangementembodying the present invention, some parts being in section and broken away and supporting members being omitted.

Referring to the drawings there is shown a. grinding orpulverizing mill 1 which in its particular structure forms no part of the present invention, and may he the same or similar to the pulverizing or grinding mill shown in United States Patent No. 922,496, granted to J. W. Fuller, Jr., on May 25, 1909, but it is to be understood that the present invention is not limited in use to the mill illustrated since the invention may be adapted to other mills On top of the mill 1 and communicating with the pulverizing chamber is a separation chamber 2 from which there leads a pipe 3, and this pipe because of its function may be termed a suction pipe. The end of the pipe 3 remote from the chamber 2 communicates with the intake or a fan 4 or other device of like character designed to produce 'subatmospheric pressure within the pipe 3, and thereby cause a current of air therein from the separation chamber 2 to the fan 4. The outlet side of the fan is connected by a pipe 5 tea separator 6 which may be of the cyclone type and follow any desired form of such separator adapted to the purpose of the present invention, or it'may'be indicative of any other type of separator suited to the invention, The separator 6 is ing chamber thereof as indicated at 9, the arrangement being such that the inflowmg stream of air will cause more or less agitation of the material within the pulverizing chamber. v

At any suitable point in the pipe 8 there is located a vent pipe 10 provided with a valve 11 which may be arranged to permit the escape of air from the pipe 8 to the atmosphere, and thus regulate the amount of air directed by the return pipe 8 intovthe mill 1.

Pulverulent material from the mill 1 finds escape by gravity through a discharge pipe 12 leading into a conveyer 13 by means of which the material maybe moved to any suitable point of disposal. Connected to the discharge pipe 12 is an auxiliary pipe 14 having a gently curved portion 15 where enteriug the pipe 12 and this auxiliary pipe 14- leads to the pipe 3 which it enters by a gently curved portion 16 opening into the pipe 3 in substantially the direction of flow of air through this pipe toward the fan 4.

The hopper 7 serving as a collector for fine material carried by the air into the separator 6 is connected by a pipe 17 to the conveyer 13.

The fan 4 is driven by power in any suitable vmanner and is arranged so that the velocity of airin the pipe 3 may be regulated as desired.

The grinding machine of the character illustrated in the drawings is one using screens for separation. Not only is the air within the mill agitated, but a certain proportion of the fine material is carried by the air stream through the pipe 3 and pump or fan 1 into the separator 6 in which the fine material is-deposited from the air. The degree of fineness of the material carried by the air depends upon the velocity of the latter and this may be regulated to a nicety by driving the fan 1 at such speed as will establish the desired flow of air, difl'erent speeds of the fan meaning difi'ferent speeds of flow of the air through the pipe 3.

The speed of the fan 4 will depend upon the specific gravity of the material being treated and the desired fineness of the prodnot, so that no particular directions can be given for the speed of the fan.

The return pipe 8 enters directly into the top of the mill and is for the purpose of replacing some of the air that has already been removed and increase thecirculation inside of the mill proper, besides assisting in forcing material through the screens, which material finds its way through the outlet pipe 12 and into the conveyer 13.

The auxiliary pipe 14 which may be smaller than the other'pipes and connecting the discharge spout of the mill to the suction pipe close to the fan, causes an induced draft through the screens and mill and partially oifsets' the suction from the mill to the. fan. This has a tendency to keep the material in the bottom of the grinding zone.

of the mill and has been found to greatly increase the outputof the mill.

The dust .collector comprising the separator 6 with its termination 7 or any other type of dust collector suited for the purpose of the present invention is for the purpose of delivering the fine material extracted from the mill by the fan to the conveyer Where it may mix with the fine material reaching it directly from the mill.

With such an arrangement actual practice has shown an output of six tons per hour with a fineness of from eighty-nine to ninety passing through a two hundredimesh screen as against from three tothree and onehalf tons of a fineness of eighty-four to eighty-five passing through a two hundred mesh screen, but without the exhaust'system of the present invention, although treating the same material in the same factory.

What is claimed is V v 1. The combination with a pulverizing mill having means for exhausting air together with fine material from the pulverizing chamber above the pulverizing elements and for returning the air freed from the fine material to the pulverizing chamber 3' from the mill, and means for directingthe fine material extracted from the air 'exhaustedfrom the mill to the' material eseaping by gravity from the mill.

2. The combination with a pulverizing mill having means for exhausting air together with fine material therefrom, of an outlet for the escape of material from the a mill by gravity, and an auxiliary air exhaust duct between the intake side of the air exhausting means and the outlet of the mill provided for the escape of material therefrom by gravity.

3. The combination with a. pulverizing 3 mill having an outlet for the escape of pulverized material therefrom by gravity, of an air duct communicating with the pulverizing chamber of the mill, an air exhausting means connected with the air duct, a dust collector into which the air exhausting means discharges, an air pipe leading from the dust collector to the pulverizing chain-- ber of the mill and an auxiliary air pipe leading from the outlet for the escape of material from the mill by gravity to the intake side of the air exhausting means.

4. The combination with a pulverizin mill having an outlet for the escape of p verized material therefrom by gravity, of an air duct communicating with the pulver izing chamber of the mill, an air exhausting its collector into whichlthe air exhaust means 'iary air pipe communicating with the dis charge side of the mill and with the intake side of the air exhausting means by gentle curves. i

5. The combination with a. pulverizing mill, of a discharge duet for the escape of material. from the mill by gravity, means for exhausting air from the pulverizing chamber of the mill'and from the discharge duct, and means for directing air .underv p 7 material escaping from the 111111, and-means pressure to the pulverizing chamber of the m1ll.

6. The combination with a pulverizing mill, of a discharge'duct for the escape of material therefrom by gravity, an air exhaust duct communicating with the pulverizing chamberof the mill, an air exhaust duct communicating with'the said discharge duct ofthe mill, air exhausting means havthe air exhaust means to the interior of the pulverizing chamber.

7. The combination with a pulverizing mill, of means for j-e'xhausting air from above and below the pulverizing elements of the mill, 'and means for introducing air under pressure into the mill at a point above the pulverizingelements of the mill.

-8. The combination with a pulverizing -mi1l, of means for exhausting airfrom the mill both above and below the pulverizing elements, means for the'escape of material from. the mill by gravity, means for separating from the air withdrawn from above the pulverizing elements the fine material thereby exhausted from the mill, means for delivering fine material so separated to the for directing-the clean air under pressure to the pulverizing chamber above the pulverizing elements, I

In testimony, that I claim the foregoing as my own, I have hereto aflixed my signature in the presence of two witnesses EDWARD J. STECKLE.

ing common communication on the intake Witnesses: side with both air exhaust ducts, and means G. J. Pinon, .for directing air from the pressure-side of I M, A. COMP'IDN. 

